luck of the draw, my friend. it sucks when it happens but the figure isnt broken. if thats your only flaw i wouldnt worry about it. what you can do is thicken the ball end with some kind of glue and let it harden. you can add more if needed or sand some off if its too tight after. works like a charm for me. i actually got my snake and ninja to have stiffer ball joints this way, now they can pose just fine - similar to the newer joint styles (without the ratcheting of course). 
